Varunayan

Varunayan is a climate data toolkit from Saket Lab at IIT Bombay. It takes the tedious part out of working with gridded weather data: you give it a bounding box, a GeoJSON boundary or a point, and it fetches the data, clips it to your region and returns a clean daily or monthly time series.

It pulls from four sources:

• ERA5 reanalysis from Copernicus, at 0.25° resolution from 1940 onwards, including pressure-level variables.
• IMD gridded rainfall and temperature for India, from 1901 onwards.
• HadEX3 global indices of climate extremes.
• CRU TS monthly climate grids at 0.5° resolution from 1901 onwards.

On top of the downloads it computes heat stress measures (UTCI, wet bulb globe temperature, heat index and humidex), aggregates temperature to the country or state level, and includes helpers for monsoon analysis.

The Python package installs from PyPI and works both as a library and from the command line. varunayanR is its R counterpart with the same data sources and a similar interface. Both are MIT licensed. ERA5 downloads need a free Copernicus Climate Data Store account.